What is meteorite iron? How does it appear on earth? You will find answers to these and other questions in the article. Meteorite iron is the metal found in meteorites and consisting of several mineral phases: tenite and kamasite. It makes up most of the metal meteorites, but there are also other types. Consider meteorite iron below.
Structure
During etching of a polished section, the structure of meteorite iron appears in the form of the so-called Widmanstetten figures: intersecting beam-strips (kamasit), bordered by shiny narrow ribbons (tenit). Sometimes you can see polygonal fields.
A fine-grained mixture of tenite and kamasite forms plessite. The iron we are considering in meteorites such as hexahedrites, which is almost entirely composed of kamasite, forms a structure in the form of parallel thin lines called neman lines.
Application
In ancient times, people did not know how to make metal from ore, so its only source was meteorite iron. It is proved that elementary tools from this substance (identical in shape to stone ones) were created back in the Bronze and Neolithic era. From it were made a dagger, found in the tomb of Tutankhamun, and a knife from the Sumerian town of Ur (about 3100 BC), beads found 70 km from Cairo, in places of eternal rest, in 1911 (about 3000 BC A.E.).
Tibetan sculpture was also created from this substance. It is known that the king of Numa Pompilius (Ancient Rome) had a metal shield made from "a stone that fell from the sky." In 1621, for Jahangir (the ruler of an Indian principality), a dagger, two sabers, and a tip of a spade were forged from heavenly iron.
A saber made of this metal was donated to Sovereign Alexander I. According to legend, the swords of Tamerlane also had a cosmic origin. Today, celestial iron is used in jewelry production, but most of it is used for scientific experiments.
Meteorites
Meteorites are 90% metal. Therefore, the first person began to use heavenly iron. How to distinguish it from the earth? This is very simple, because it contains about 7-8% of nickel impurities. It is not for nothing that in Egypt he was nicknamed star metal, and in Greece - heavenly metal. This substance was considered very rare and expensive. It's hard to believe, but it was previously framed in gold frames.
Star iron is not resistant to corrosion, therefore, products from it are rarely found: they simply could not survive to this day, since they crumbled from rust.
According to the detection method, iron meteorites are divided into falls and finds. Falls are called such meteorites, the decrease of which was visible and which people were able to find shortly after their landing.
Finds are meteorites discovered on the surface of the Earth, but the fall of which no one has observed.
Meteorites falling
How does a meteorite fall to Earth? Today, more than a thousand falls of heavenly wanderers are recorded. Only meteors are included in this list, the passage of which through the earth's atmosphere is recorded by automatic technology or by observers.
Star stones enter the atmosphere of our planet at a speed of about 11-25 km / s. At this speed, they begin to warm up and glow. Due to ablation (carbonization and blowing away of the substance of the meteorite with a counter flow of particles), the weight of a body flying to the Earth's surface can be less, and sometimes significantly less, than its mass at the entrance to the atmosphere.
The fall of a meteorite to the Earth is an amazing phenomenon. If the meteorite is small, then at a speed of 25 km / s it will burn without a trace. As a rule, out of tens and hundreds of tons of primary mass, only a couple kilograms and even grams of a substance reaches the ground. Traces of the combustion of celestial bodies in the atmosphere can be found over almost the entire trajectory of their fall.
The fall of the Tunguska meteorite
This mysterious event occurred in 1908, on June 30. How did the Tunguska meteorite fall? A celestial body fell in the area of the Tunguska Podkamennaya river at 7.15 a.m. local time. It was an early morning, but the villagers had long woken up. They were engaged in current affairs, which in village courtyards require constant attention from the very sunrise.
Podkamennaya Tunguska itself is a full-flowing and mighty river. It flows on the lands of the present Krasnoyarsk Territory, and originates in the Irkutsk region. It tears through taiga wilderness areas, replete with wooded high banks. This is a godforsaken land, but it is rich in minerals, fish and, of course, impressive hordes of mosquitoes.
The mysterious event began at 6.30 a.m. local time. Residents of villages located along the banks of the Yenisei, saw in the sky a fireball of impressive size. He moved from south to north, and then disappeared over the taiga open spaces. At 7 hours and 15 minutes a bright flash lit up the sky. After a while there was a terrible roar. The earth shook, glass flew out of the windows in the houses, the clouds turned red. They kept that color for a couple of days.
Observatories located in different corners of the planet recorded a blast wave of great power. Next, people wanted to know what happened and where. It is clear that in the taiga, but it is very large.
It was not possible to organize a scientific expedition, as there were no wealthy philanthropists willing to pay for such studies. Therefore, scientists at first decided only to interview eyewitnesses. They talked with Evenki and Russian hunters. Those said that at first a strong wind blew and a loud whistle sounded. Further, the sky flooded with red light. After a thunderclap, the trees began to light up and fall. It got really hot. After a couple of seconds, the sky shone even stronger, and the thunder sounded again. A second sun appeared in the sky, which was much brighter than the usual luminary.
Everything was limited to these indications. Scientists decided that a meteorite fell in the Siberian taiga. And since he landed in the Podkamennaya Tunguska zone, they called him Tunguska.
The first expedition was equipped only in 1921. Its initiators were academicians Fersman Alexander Evgenievich (1883-1945) and Vernadsky Vladimir Ivanovich (1863-1945). This trip was led by Kulik Leonid Alekseevich (1883-1942), a leading specialist on meteorites in the USSR. Then several more scientific trips were organized in 1927-1939. As a result of these studies, the assumptions of scientists were confirmed. In the Tunguska Podkamennaya river basin, a meteorite really fell. But the huge crater that was supposed to create the fallen body was not discovered. They found no crater at all, not even the smallest one. But then they found the epicenter of a powerful explosion.
It was installed in the trees. They stood as if nothing had happened. And around them in a radius of 200 km lay a felled forest. The prospectors decided that the explosion occurred at an altitude of 5-15 km above the ground. In the 60s it was established that the force of the explosion was equal to the power of a hydrogen bomb with a capacity of 50 megatons.
Today, about the fall of this celestial body, there are a huge number of assumptions and theories. The official verdict says that it was not a meteorite that fell on Earth, but a comet - a block of ice with tiny tiny cosmic particles embedded in it.
Some researchers believe that an alien spaceship crashed over our planet. In general, almost nothing is known about the Tunguska meteorite. No one can name the parameters and mass of this stellar body. Surveyors will probably never come to the only true concept. After all, how many people, so many opinions. Therefore, the mystery of the Tunguska guest will give birth to ever new hypotheses.